Singlet–Triplet Splittings in the Luminescent Excited States of Colloidal Cu+:CdSe, Cu+:InP, and CuInS2 Nanocrystals: Charge-Transfer Configurations and Self-Trapped Excitons

Knowles, Kathryn E.; Nelson, Heidi D; Kilburn, Troy B.; Gamelin, Daniel R.

doi:10.1021/jacs.5b08547

Cited by 215 publications

(471 citation statements)

References 61 publications

(140 reference statements)

Supporting

Mentioning

405

Contrasting

Unclassified

Order By: Relevance

“…46 However, recent work has unambiguously demonstrated that the PL in CP CIS QDs originates from the radiative recombination of a delocalized CB electron with a hole localized on a Cu + ion. 31,47,48 Nevertheless, the nature of the hole localization process (i.e., self-trapping onto a regular Cu + ion 48 or capture by a native defect, such as Cu In 2– ) has yet to be unravelled. 31 …”

Section: Results and Discussionmentioning

confidence: 99%

Highly Luminescent Water-Dispersible NIR-Emitting Wurtzite CuInS₂/ZnS Core/Shell Colloidal Quantum Dots

et al. 2017

View full text Add to dashboard Cite

Copper indium sulfide (CIS) quantum dots (QDs) are attractive as labels for biomedical imaging, since they have large absorption coefficients across a broad spectral range, size- and composition-tunable photoluminescence from the visible to the near-infrared, and low toxicity. However, the application of NIR-emitting CIS QDs is still hindered by large size and shape dispersions and low photoluminescence quantum yields (PLQYs). In this work, we develop an efficient pathway to synthesize highly luminescent NIR-emitting wurtzite CIS/ZnS QDs, starting from template Cu2-xS nanocrystals (NCs), which are converted by topotactic partial Cu+ for In3+ exchange into CIS NCs. These NCs are subsequently used as cores for the overgrowth of ZnS shells (≤1 nm thick). The CIS/ZnS core/shell QDs exhibit PL tunability from the first to the second NIR window (750–1100 nm), with PLQYs ranging from 75% (at 820 nm) to 25% (at 1050 nm), and can be readily transferred to water upon exchange of the native ligands for mercaptoundecanoic acid. The resulting water-dispersible CIS/ZnS QDs possess good colloidal stability over at least 6 months and PLQYs ranging from 39% (at 820 nm) to 6% (at 1050 nm). These PLQYs are superior to those of commonly available water-soluble NIR-fluorophores (dyes and QDs), making the hydrophilic CIS/ZnS QDs developed in this work promising candidates for further application as NIR emitters in bioimaging. The hydrophobic CIS/ZnS QDs obtained immediately after the ZnS shelling are also attractive as fluorophores in luminescent solar concentrators.

show abstract

Section: Results and Discussionmentioning

confidence: 99%

Highly Luminescent Water-Dispersible NIR-Emitting Wurtzite CuInS₂/ZnS Core/Shell Colloidal Quantum Dots

et al. 2017

View full text Add to dashboard Cite

show abstract

“…Upon photoexcitation, the 1S holes nonradiatively moved from the valence band to the impurity in the core 30. The luminescence of the g‐QDs is attributed to the radiative recombination of the conduction band 1S electrons with the impurity holes 30.…”

Section: Resultsmentioning

confidence: 99%

Optoelectronic Properties in Near‐Infrared Colloidal Heterostructured Pyramidal “Giant” Core/Shell Quantum Dots

et al. 2018

View full text Add to dashboard Cite

Colloidal heterostructured quantum dots (QDs) are promising candidates for next‐generation optoelectronic devices. In particular, “giant” core/shell QDs (g‐QDs) can be engineered to exhibit outstanding optical properties and high chemical/photostability for the fabrication of high‐performance optoelectronic devices. Here, the synthesis of heterostructured CuInSexS2− x (CISeS)/CdSeS/CdS g‐QDs with pyramidal shape by using a facile two‐step method is reported. The CdSeS/CdS shell is demonstrated to have a pure zinc blend phase other than typical wurtzite phase. The as‐obtained heterostructured g‐QDs exhibit near‐infrared photoluminescence (PL) emission (≈830 nm) and very long PL lifetime (in the microsecond range). The pyramidal g‐QDs exhibit a quasi‐type II band structure with spatial separation of electron–hole wave function, suggesting an efficient exciton extraction and transport, which is consistent with theoretical calculations. These heterostructured g‐QDs are used as light harvesters to fabricate a photoelectrochemical cell, exhibiting a saturated photocurrent density as high as ≈5.5 mA cm−2 and good stability under 1 sun illumination (AM 1.5 G, 100 mW cm−2). These results are an important step toward using heterostructured pyramidal g‐QDs for prospective applications in solar technologies.

show abstract

“…24,25 Furthermore, impurity doping of perovskite thin films has been shown to improve their performance in solar cells. 26−28 Recently, Mn 2+ doping in colloidal CsPbCl 3 perovskite NCs has been achieved by a direct synthesis method, in which PbCl 2 and MnCl 2 precursors were mixed in the desired ratio, leading to NCs with the characteristic Mn 2+ emission.…”

Section: Introductionmentioning

confidence: 99%

Highly Emissive Divalent-Ion-Doped Colloidal CsPb_1–xM_xBr₃ Perovskite Nanocrystals through Cation Exchange

et al. 2017

View full text Add to dashboard Cite

Colloidal CsPbX3 (X = Br, Cl, and I) perovskite nanocrystals (NCs) have emerged as promising phosphors and solar cell materials due to their remarkable optoelectronic properties. These properties can be tailored by not only controlling the size and shape of the NCs but also postsynthetic composition tuning through topotactic anion exchange. In contrast, property control by cation exchange is still underdeveloped for colloidal CsPbX3 NCs. Here, we present a method that allows partial cation exchange in colloidal CsPbBr3 NCs, whereby Pb2+ is exchanged for several isovalent cations, resulting in doped CsPb1–xMxBr3 NCs (M= Sn2+, Cd2+, and Zn2+; 0 < x ≤ 0.1), with preservation of the original NC shape. The size of the parent NCs is also preserved in the product NCs, apart from a small (few %) contraction of the unit cells upon incorporation of the guest cations. The partial Pb2+ for M2+ exchange leads to a blue-shift of the optical spectra, while maintaining the high photoluminescence quantum yields (>50%), sharp absorption features, and narrow emission of the parent CsPbBr3 NCs. The blue-shift in the optical spectra is attributed to the lattice contraction that accompanies the Pb2+ for M2+ cation exchange and is observed to scale linearly with the lattice contraction. This work opens up new possibilities to engineer the properties of halide perovskite NCs, which to date are demonstrated to be the only known system where cation and anion exchange reactions can be sequentially combined while preserving the original NC shape, resulting in compositionally diverse perovskite NCs.

show abstract

Singlet–Triplet Splittings in the Luminescent Excited States of Colloidal Cu⁺:CdSe, Cu⁺:InP, and CuInS₂ Nanocrystals: Charge-Transfer Configurations and Self-Trapped Excitons

Cited by 215 publications

References 61 publications

Highly Luminescent Water-Dispersible NIR-Emitting Wurtzite CuInS₂/ZnS Core/Shell Colloidal Quantum Dots

Highly Luminescent Water-Dispersible NIR-Emitting Wurtzite CuInS₂/ZnS Core/Shell Colloidal Quantum Dots

Optoelectronic Properties in Near‐Infrared Colloidal Heterostructured Pyramidal “Giant” Core/Shell Quantum Dots

Highly Emissive Divalent-Ion-Doped Colloidal CsPb_1–xM_xBr₃ Perovskite Nanocrystals through Cation Exchange

Contact Info

Product

Resources

About

Singlet–Triplet Splittings in the Luminescent Excited States of Colloidal Cu+:CdSe, Cu+:InP, and CuInS2 Nanocrystals: Charge-Transfer Configurations and Self-Trapped Excitons

Cited by 215 publications

References 61 publications

Highly Luminescent Water-Dispersible NIR-Emitting Wurtzite CuInS2/ZnS Core/Shell Colloidal Quantum Dots

Highly Luminescent Water-Dispersible NIR-Emitting Wurtzite CuInS2/ZnS Core/Shell Colloidal Quantum Dots

Optoelectronic Properties in Near‐Infrared Colloidal Heterostructured Pyramidal “Giant” Core/Shell Quantum Dots

Highly Emissive Divalent-Ion-Doped Colloidal CsPb1–xMxBr3 Perovskite Nanocrystals through Cation Exchange

Contact Info

Product

Resources

About

Singlet–Triplet Splittings in the Luminescent Excited States of Colloidal Cu⁺:CdSe, Cu⁺:InP, and CuInS₂ Nanocrystals: Charge-Transfer Configurations and Self-Trapped Excitons

Highly Luminescent Water-Dispersible NIR-Emitting Wurtzite CuInS₂/ZnS Core/Shell Colloidal Quantum Dots

Highly Luminescent Water-Dispersible NIR-Emitting Wurtzite CuInS₂/ZnS Core/Shell Colloidal Quantum Dots

Highly Emissive Divalent-Ion-Doped Colloidal CsPb_1–xM_xBr₃ Perovskite Nanocrystals through Cation Exchange